IMHO: the acceleration curve into point-of-no-return was when Microsoft decided to go hard on AI, and saw GitHub's Copilot as one of the key inflection points they were going to use to do so - even going so far to adopt the Copilot brand across the entire company.

Before that, it still felt like there _some_ degree of autonomy and ability to think about the developer experience on the platform as a whole. Once ChatGPT took off and MSFT decided that they were going to go hard on AI, though, Copilot (and therefore GitHub) became too important to Microsoft to leave alone.

I kinda suspect the slide was inevitable anyway, given how acquisitions tend to go. But IMO, Copilot was the tsunami that washed the octocat out to sea.